Lubricating oil composition



Patented Nov. 19, 1940 "UNITED STATES LUBRICATING OIL COMPOSITION Chester L. Read, Westfield, N. J., assignor to Standard Oil Development Company, a. corporation of Delaware No Drawing.

Application February 10, 1938,

Serial No. 189,761

9 Claims.

The present invention relates to improvements in lubricating oils, especially those lubricating oils used at high temperatures under oxidizing conditions as, for example, motor oils for automobile 5 engines, aeroplane engines, Diesel engines, and the like. The invention particularly relates to a composition comprising a highly aromatic stable compound or mixture of compounds and a suitable lubricating oil. The composition and meth- 10 d of manufacturing the same will be fully understood by the following description.

There has been considerable difiiculty in the past in providing lubricants which are satisfactory for all uses and purposes. The relatively 15 highly refined lubricating oils suitable for high temperature operation do not form appreciable quantities of sludge in the crank case but, on the other hand, these highly refined oils exhibit tendencies to cause excessive ring sticking. Oils not 20 highly refined as, for example, not being subjected to clay or sol ent extraction processes, are of dark color and show little tendency to cause ring sticking or to deposit carbon in the ring slits.

However, these oils do tend to form appreciable 1 5 quantities of sludge, thereby greatly detracting from their value and use.

The present invention provides a lubricating oil which is entirely stable and does not oxidize under the extreme oxidizing conditions prevailing 30 in internal combustion engines. These improved lubricating compositions are secured by incorporating in a suitable lubricant a soluble highly aromatic material. This improved lubricating oil composition minimizes ring sticking, does not 35 sludge and has improved lubricating properties.

These addition agents may be any highly aromatic compound of suitable boiling range which are soluble in a lubricating oil. These aromatic materials of the present invention are preferably selected from the class of hydrogenated neutral hydrocarbon oils, hydrogenated neutral rosin oils, hydrogenated phenanthrene homologs and the like which have a boiling point of at least 175 C. Aromatic materials derived from petroleum source as, for example, the extract derived in .solvent treating operations in which a solvent having a preferential selectivity for compounds having a lower ratio of hydrogen to carbon as compared to compounds having a high ratio of hydrogen to 0 carbon, are employed. Solvents of this type are,

for example, phenol, liquid sulphur dioxide, furfural nitrobenzene, cresylic acid, acetonitrile, aniline, acetone, and the like. If solvents having a preferential selectivity for compounds having a 55 higher ratio of hydrogen to carbon, as compared to compounds having a lower ratio of hydrogen to carbon, are employed as, for example, liquid normally gaseous hydrocarbons, i. e., liquid propane and butane, the materials suitable for the present no invention are to be found in the rafllnate. Preferred compounds are secured from aromatic type crudes, particularly after the removal of the asphalt and wax. The materials thus secured may be hydrogenated to secure a substantially saturated aromatic product, which does not boil below the lubricating oil boiling range.

Other materials entirely suitable are high boiling petroleum fractions which have a narrow boiling range. Preferred narrow boiling fractions of this type boil in the range from 300 to 500 F. at one millimeter mercury pressure and have a viscosity index of about -100 or lower. These materials may be secured from aromatic type crudes as, for example, from California or Venezuela crude'by distilling and selecting the desired narrow boiling fraction. These fractions may also be secured by segregating the aromatic fraction secured when solvent treating an aromatic or paraflinic type crude of suitable boiling range. When the narrow boiling range fractions secured in the desired manner are not initially saturated or of high stability toward oxidation, they may be hydrogenated. These narrow boiling range fractions may also be subjected to acid or clay treatment or to a similar process in order to improve their stability.

Especially desirable materials for the present invention are the materials secured by hydrogenating a neutral rosin oil, neutral wood tar oil, abietenes, abietines, retenes and homologous materials. Preferred materials are secured by decarboxylating rosin acids as, for example, abietlc acid, pimaric acid, and the like, followed by the hydrogenation of decarboxylated products to produce a fully saturated product having a boiling point above 300 C. These materials are entirely stable and, furthermore, due to their relatively high boiling point, will not distill out of the oil when in service and will not adversely affect the flash characteristics of the oil.

These phenanthrene homologs, neutral rosin oils, abietenes, abietines, decarboxylated rosin acids, and the like may be secured in any manner whatsoever as, for example, by the destructive distillation of rosin, coniferous woods and the like. These materials are then hydrogenated to produce a substantially saturated product. A desirable manner of securing a preferred type of addition agent is to decarboxylate rosin acid as, for example, abietlc acid and pimaric acid, and then hydrogenate the decarboxylated product.

This hydrogenation is conducted in a manner whereby hydrogen is added to a liquid neutral product or a liquid decarboxylated product to substantially saturate the molecule. The hydrogenation is conducted in the presence of a suitable catalyst which is preferably a metal selected from group VIII of the periodic table. The pressures employed are in the range from 1500 to 6000 pounds per square inch and the temperatures at a Refractive index range from 140 to 250 0. Preferred pressures are at least-2000 pounds per square inch and the temperatures in the range from 140 to 250 C. Preferred hydrogenation temperatures are from 175 to 195 C. A particularly desirable catalyst is nickel on a suitable carrier. The hydrogenation process may be one-stage or may be conducted in several stages. The hydrogenation is conducted for a sufliclent time to secure a substantially saturated product. By this process, for example. rosin oil having a boiling point in the range from about 350 to 360 0.. a density 20/20 of about .97, a refractive index of about 1.53 may be hydrogenated to produce a product having a boiling point in the range from about 350 to 360, a density 20/20 of about 0.94. a refractive index of about 1.51. The product before hydrogenation contained 88.6% carbon and 11.7% hydrogen, whereas after hydrogenation the product contained approximately 86.8% carbon and 13.3% hydrogen.

These materials may be added to the lubricating oil in any desired proportion. depending upon the type and grade of lubricating oil as well as upon the conditions under which the oil is to be utilized. Thus these materials may be added to the lubricating oil in proportions from about 0.5 to 20%. It is, however. preferred to add in a concentration from about 5 to 10%.

The following examples are given for the purpose of illustrating the invention and are not to limit the invention in any manner whatsoever.

Example 1.

A neutral rosin oil was prepared by decarboxylating abietic acid. This material was then hydrogenated in the liquid state at a temperature above 140 C. and at a pressure above 1500 pounds per square inch. The product secured was a substantially saturated hydroabietene. This hydrogenated material had the following inspection:

Neutralization N 0.05

Sligh" 4 Gravity 14.8 Flash 295 Viscosity 100 168.1 Viscosity 210 39 Color Straw Boiling range C 350-365 'Sligh test: This determines the tendency of an oil to sludge under oxidizing conditions as described in the A. S. T. M. Report Committee D2. age 22, 1927. exce t that the time of run was increased rom 2% hours to 4 hours in order to secure a more accurate test and comparison. I

This material was then blended with a lubri-. eating oil S. A. E. 50 in a concentration of 5% and the neutralization number and Sligh test were then run on the unblended oil and on the blend. The results of these tests were as follows:

30 in a concentration of The lubricating oil and the blend had the following inspection:

- il)% lubricating oil, Lubricating B. A. E. l 0 oil. 8. A. E. hydrogenated abictene GravityA. P. I....-. 28.8 27.3 Viscosity Saybolt F- 513 447 Viscosity Boybolt 210 F 05. 8 58. 4 Conradson carbon 0. I) 0. 19

The base oil and the blend were then tested in the committee fuel research engine at a Jacket temperature of 375 F. The results of this test were as follows:

Fourteen hour C. F. R. motor engine tests at 375 F. jacket temperature with 2 pounds oil charge Rinfnstick- F m Demeritt g (tlmrams of cara is n pcrcen n in rings. demerit of reierslits and once No Degrooves grees Lubricating oil,

8. A. E. 30 3.64 100 3 675 3.52 90% lubricating oil. 8. A. E. 30.. 2.36 60 l 00 1.18 10% hydrogenated abietenc The spent oil from the respective tests was tested for saponiflcatlon number with the following results:

Saponiflcation No. Lubricating oil. S. A. E. 30 12.8 90% lubricating 011, S. A. E. 30 6.6 10% hydrogenated abietene.

the following claims in which it is desired to claim all novelty insofar as the prior art permits.

I claim:

1. Improved lubricating oil composition comprising a lubricating oil containing a small amount of a hydrogenated phenanthrene homolog boiling in the range above C.

2. Composition in accordance with claim 1 in which the phenanthrene homolog is present in the concentration of from about 0.5 to about 20%.

3. Composition in accordance with claim 1 in which said phenanthrene homolog is present in the concentration of from about 5 to about 10%.

4. Improved lubricatingoil composition comprising a lubricating oil and a small amount of a hydrogenated neutral rosin oil boiling in the range above 300 C.

5. Composition in accordance with claim 4 in which said rosin oil is present in the concentration of from about 5 to about 10%.

6. Improved lubricating oil composition comprising a lubricating oil and a small amount of a rosin acid which has been decarboxylated and in the presence of a catalyst which is selected from group 8 of the periodic table.

9. An improved lubricating oil composition comprising a lubricating oil containing a small amount of a material of the group consisting of a hydrogenated phenanthrene homolog boiling in the range above 175 0., hydrogenated neutral rosin oil boiling in the range above 300 0., and a rosin acid which has been decarboxylated and then-hydrogenated to substantially saturate the 10 molecule.

CHES ER L. READ. 

